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Communication For Initializing Impossible

Detecting condition:

Defective harness connector.
Defective power steering control module.

Trouble symptom:

Communication is impossible between the power steering control module and Subaru Select Monitor.
After starting the engine, the STEERING warning light does not illuminate but steering effort is heavy.

Wiring diagram:

Electric power steering system Ref. to Electric Power Steering System .

Fig 1: Power Steering Control Module Circuit Diagram

G09488922

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK IGNITION SWITCH.	Is the ignition switch ON?	Go to step 2 .	Turn the ignition switch to ON, and select the power steering mode using the Subaru Select Monitor.
2 CHECK BATTERY. Turn the ignition switch to OFF. Measure the battery voltage.	Is the voltage 12 V or more?	Go to step 3 .	Charge or replace the battery.
3 CHECK BATTERY TERMINAL.	Is there poor contact at battery terminal?	Replace or tighten the battery terminal.	Go to step 4 .
4 CHECK SUBARU SELECT MONITOR COMMUNICATION. Turn the ignition switch to ON. Using the Subaru Select Monitor, check whether communication to other systems can be executed normally.	Is the system name displayed on Subaru Select Monitor?	Go to step 8 .	Go to step 5 .
5 CHECK SUBARU SELECT MONITOR COMMUNICATION. Turn the ignition switch to OFF. Disconnect the power steering control module connector. Turn the ignition switch to ON. Check whether communication to other systems can be executed normally.	Is the system name displayed on Subaru Select Monitor?	Replace the power steering control module. Ref. to Power Steering Control Module .	Go to step 6 .
6 CHECK HARNESS CONNECTOR BETWEEN EACH CONTROL MODULE AND DATA LINK CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from EControl Module, VDC Control Module, airbag Control Module and body integrated unit. CAUTION: When disconnecting the connector from airbag Control Module, always follow the precautions on AB article. Ref. to CAUTION , General Description. Measure the resistance between data link connector and chassis ground. Connector & terminal (B40) No. 7 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 7 .	Repair the short circuit to ground in harness and connector between each control module and data link connector.
7 CHECK HARNESS CONNECTOR BETWEEN POWER STEERING CONTROL MODULE AND DATA LINK CONNECTOR. Turn the ignition switch to ON. Measure the voltage between the power steering control module and chassis ground. Connector & terminal (B40) No. 7 (+) - Chassis ground (-):	Is the voltage less than 1 V?	Go to step 8 .	Repair the short circuit to power supply in harness and connector between each control module and data link connector.
8 CHECK HARNESS CONNECTOR BETWEEN POWER STEERING CONTROL MODULE AND DATA LINK CONNECTOR. Measure the resistance between the power steering control module connector and the data link connector. Connector & terminal (B450) No. 2 - (B40) No. 7:	Is the resistance less than 0.5 Ω?	Go to step 9 .	Repair the open circuit or poor contact of harness and connectors between the power steering control module and data link connector.
9 CHECK POWER STEERING CONTROL MODULE CONNECTOR INSTALLATION. Turn the ignition switch to OFF.	Is the power steering control module connector inserted into the power steering control module until the clamp locks?	Go to step 10 .	Insert the power steering control module connector into the power steering control module.
10 CHECK POWER SUPPLY CIRCUIT. Turn the ignition switch to OFF. Disconnect the power steering control module connector (B452). Turn the ignition switch to ON. (Engine OFF) Measure the ignition power supply voltage between the power steering control module connector and chassis ground. Connector & terminal (B450) No. 1 (+) - Chassis ground (-): (B452) No. 2 (+) - Chassis ground (-):	Is the voltage 10 - 15 V?	Go to step 11 .	Repair the open circuit of harness or the poor contact of connector between the power steering control module and the battery.
11 CHECK HARNESS CONNECTOR BETWEEN POWER STEERING CONTROL MODULE AND CHASSIS GROUND. Turn the ignition switch to OFF. Disconnect the connector from the power steering control module. Measure the resistance in the harness between the power steering control module and chassis ground. Connector & terminal (B452) No. 1 - Chassis ground:	Is the resistance less than 0.5 Ω?	Go to step 12 .	Repair the open circuit or poor contact of the harness between the power steering control module and chassis ground.
12 CHECK POOR CONTACT OF CONNECTOR.	Is there poor contact of power steering control module power supply, ground circuit and data link connector?	Repair the connector.	Replace the power steering control module. Ref. to Power Steering Control Module .